Landau-level lifetimes in PbTe nipi superlattices, PbTe/PbEuTe and InAs/AlSb quantum wells

Landau-level lifetimes are determined from saturation cyclotron resonance (CR) in wide parabolic wells, quantum wells and bulk PbTe-Pb1-xEuxTe systems. These narrow gap structures exhibit strong band non-parabolicity necessary to terminate the normally equi-spaced Landau-level ladder. It was not possible to saturate the bulk sample, but short lifetimes, of between 1.5 and 8 ps, were obtained for the wide parabolic well and the quantum well, respectively, utilising a multi-level rate equation model. We also report the first pump-probe cyclotron resonance result in an InAs-AlSb quantum structure. The pump-probe experiment provides a direct determination of the lifetime, giving tau = 40 ps in this InAs-AlSb sample. This shows good agreement with an 8 x 8k.p calculation. (C) 1998 Elsevier Science B.V. All rights reserved.